1. Field of the Invention
The present invention relates to a light source device and an image projection device.
2. Description of the Related Art
For a light source device having a light emitting tube that is used for a projector (an image projection device) or the like, cooling of the light emitting tube may have been required. In the light emitting tube, due to an effect of heat convection, an increase in temperature of an upper portion is greater relative to that of a lower part with respect to a center line direction (i.e., a lower part with respect to the gravitation). Thus, a temperature difference tends to occur between the upper portion and the lower portion. Such a temperature difference can be a cause of breakage of the light emitting tube or a cause of degradation of the light emitting tube. For cooling a light emitting tube, it is desired that the upper portion is efficiently cooled relative to the lower portion so as to prevent a temperature difference between the upper portion and the lower portion from occurring. There are some image projection devices that can be used in two installation states. One installation state is a stationary installation state such that the image projection device is placed on a desk or the like and the image projection device is used. The other installation state is a hanging installation state such that the image projection device is hanging from a ceiling in an upside-down position and the image projection device is used.
A configuration of an image projection device has been known such that a baffle plate that rotates by its own weight is provided in a flow channel for flowing a cooling air current, so that an upper portion of a light emitting tube is efficiently cooled both in the stationary installation state and the hanging installation state. The baffle plate is for opening an upper side of the flow channel and for closing a lower side of the flow channel. Thus, a cooling air current can be guided to the upper portion (cf. Patent Document 1 (Japanese Patent No. 5378112), for example).